Transcript GM yeast in the wine industry

GMOs & Wine Media Round Table
Cape Town, 25 June 2008
GM Yeast in the wine industry
Threat or opportunity?
Florian F. Bauer
Institute for Wine Biotechnology
Department of Viticulture and Oenology
Stellenbosch University
Wine and technology?
Wine and technology?
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Consumer (our) expectations…
 Good aroma and taste: Wine should be of consistently high quality
 …at an affordable price
 Be healthy: Needs to satisfy WHO and specific national criteria with
regard to health regulations
 Without damaging the environment: Production needs to limit
environmental impact
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and a highly competitive global market
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Need for technological innovation
Why Yeast? The scientific case…
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What is “Yeast”?
 White powder?
 Baking tool?
 Converts sugar into alcohol?
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Unicellular organism - 1st biotechnological application (at
least 6 KY B.C. )
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S. cerevisiae 1st microorganism seen under microscope
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1st eukaryotic genome to be sequenced (1996)
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1st to be used for the production of pharmaceuticals using
recombinant DNA technology
Why Yeast? The scientific case…
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One of the most studied organisms (next to Homo sapiens)
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Well understood (≠ Homo sapiens): Best annotated genome
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Accumulated knowledge and technological know-how
 “Model system”
– Nobel prizes in medicine
 Scientific potential
– All biotechnological tools
– Understanding of genetic and biochemical networks (omics)
– Understanding the consequences of modifications (traditional
selection and genetic engineering)
– Tools for monitoring of modifications
Why Yeast? The economic case…
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Saccharomyces cerevisiae produces the four leading fermentation products
(tons/year) worldwide
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The yeast strain determines essential characteristics of the final product
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Nutritional value
Aroma
Flavour
Other applications:
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Baking
Brewing
Wine fermentation
Single cell proteins
Pharmaceuticals
Fine chemicals
Bio-ethanol
Pressing need for new yeast strains
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Increasing competition between yeast manufacturers
150 – 200 Rand/kg of speciality yeast vs 10 Rand/kg for baker’s yeast
New consumer demands
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Environmentally friendly production practices
Health-related characteristics of the fermentation products
Yeast - science and application
Scientifically best understood eukaryotic organism
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Most used microorganisms in food and other biological
production processes
=
innovation potential
Yeast and wine
 Commercial starter cultures inoculated after pressing
of grapes
 More than 200 commercial strains
 Differences in
– Processing properties
– Organoleptic properties of the wine
 Many yeast-related aspects of wine making can be
improved
 The molecular nature of many of these traits is
understood - - - but many can only be improved
through GM
The ML01 application
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Application made by Dr HJJ van Vuuren,
Director: Wine Research Centre
University of British Columbia
Vancouver, Canada
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Object of application:
 Malolactic yeast ML01
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Already approved for use by FDA (USA) and Health Canada
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What does it do?
 What is malolactic fermentation (MLF)?
– Carried out after alcoholic fermentation by lactic acid
bacteria
– Malolactic fermentation is essential in most red and many white wines for microbiological
stabilisation and wine quality.
MALOLACTIC FERMENTATION
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Malolactic fermentation
COOH
CH2
Malolactic enzyme
HOCH
(NAD+ , Mn+2 )
COOH
L- malic acid
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COOH
HOCH
CH3
L- lactic acid + CO2
Three reasons for MLF:
 Lowering of acidity (deacidification)
 Aroma compounds
 Microbiological stability
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Commercial starter cultures: Oenococcus oeni
 Tolerant to lower pH, Ethanol, SO2
 Low temperatures
The malolactic yeast ML01
 Contains two trans-genes that encode
 A malic acid transporter (from Schizosaccharomyces pombe)
 A malolactic enzyme (from Oenococcus oeni)
 Efficiently converts malate to lactate during alcoholic
fermentation
Advantages - Disadvantages
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 Reduced processing time
 Reduced risk of spoilage
 Reduced health risks
-?
 Changes to the aroma and flavour of the wine (Tasting data
appear to show tasters prefer wine made with ML01).
 Generic GM-technology related questions: Consumer
response, environmental risks
Comments: Health Canada
Wines derived from the genetically modified
wine yeast Saccharomyces cerevisiae
ML01
Health Canada has notified Dr. Hennie van Vuuren of the University of
British Columbia that it has no objection to the food use of a genetically
modified wine yeast, Saccharomyces cerevisiae ML01, for use in
winemaking in Canada, and of wines derived from the use of this yeast.
The Department conducted a comprehensive assessment of wine yeast
ML01 according to its Guidelines for the Safety Assessment of Novel
Foods. These Guidelines are based upon internationally accepted
principles for establishing the safety of foods with novel traits.
See: http://www.hc-sc.gc.ca/fn-an/gmf-agm/appro/nf-an107decdoc-eng.php
The malolactic yeast ML01
Why rejected in SA?
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Scientifically relevant questions were addressed in application
 The GM yeast shows less molecular differences (transcriptome,
proteome, metabolome) from its parental strain than the differences
observed between this parent and other commercial wine yeast
strains (health, ecology).
 The two genes are naturally present in high numbers during wine
fermentation (no significant increased risk of HGT) (ecology).
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Socio-economic reasons:
 Wine industry
 Export market
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Understandable in current situation, but will such decisions
block all development in the field?
Other developments:
Wine and Health
 Increased levels of healthy substances
 Phenolic compounds
 Resveratrol (stilbenes)
 Reduced levels of unwanted compounds
 Carcinogens
– Ethyl carbamate
 Neurotoxins
– Biogenic amines
 Asthmatic chemical preservatives
– Sulfites
Increasing levels of resveratrol
 Resveratrol
 3,5,4'-trihydroxystilbene
 cancer chemopreventive
activity
 Life prolonging in yeast and
mice
 prevention of
coronary heart
disease
 French paradox
 Increased levels of resveratrol
Phenylalanine
Resveratrol 
PAL
Cinnamic
acid
C4H
Malonyl-CoA
Coumaric acid
4CL
p-Coumarolyl CoA
VST
Resveratrol
4CL
VST
PAL = Phenylalanine ammonia-lyase
C4H = Cinnamate 4-hydroxylase
4CL = CoA-ligase
VST = Resveratrol synthase
Bio-preservation
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Winemaking heavily relies on the judicious use of SO2 to ensure
high quality and microbial stability
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Worldwide reduction in use of chemical preservatives
 health risks
 organoleptic changes
 lower nutritional value
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Consumer demand for products
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less heavily preserved
less processed
higher quality
more natural
safer
SHIFT IN RESEARCH TOWARDS BIOLOGICAL PRESERVATIVES
Leucocin activity against Listeria
yeast colonies
YEp352
LCA1
Supernatant
YEp352
Glucose oxidase activity
No
growth
Acetobacter aceti
No
growth
LCA1
Gluconobacter oxydans
Conclusion
 Would these yeast strains (ML01 and other GM yeast) be
authorised for use if the same character traits had been
obtained without the use of GM technology?
 Is there any scientific evidence to support the fear that
unpredicted and unwanted consequences may arise from the
use of these strains (product quality / health / environment)?
 Would these strains provide economic benefits to the wine
industry?
 Would these strains deliver benefits to the consumer?
…and can WE afford to ignore a technology
with such innovation potential?
Thank you